Shockproof x-ray unit



March 19, 1940. SIMON I 2,194,369

SHOCKPROOF X-RAY UNIT Filed March 1, 1939 INVENTOR r9. J/MO V.

ATTORNEY Patented Mar. 19, 1940 UNITED STATES SHOCKPROOF X-RAY UNIT Alfred Simon, Jackson Heights, Long Island,

N. Y., assignor to Westinghouse X-Ray Company, Inc., Long Island City, N. Y., a corporation of Delaware Application March 1,

7 Claims.

The present invention relates to electron discharge apparatus and particularly to X-ray or rectifying apparatus wherein the danger of an operator or patient accidentally contacting any voltage parts is entirely eliminated.

In such apparatus of the prior art it is customary to encase the discharge tube and the high tension source of energy therefor in a container and immerse the same in a body of cooling and insulating material, such as oil. This latter material, which has a higher dielectric strength than air, enables the spacing between all high tension carrying parts to be considerably less than would be required for the same applied voltage when the device is operating in air and, as a consequence, the X-ray or discharge tube may be of foreshortened length.

As a tube of this type necessarily generates appreciable heat during operation, this may be 20' dissipated somewhat by the envelope to the surrounding insulating and "cooling medium, and in addition it may be more readily dissipated by providing the anode stem of the tube with a cooling radiator connected to the anode and likewise immersed in the cooling and insulating medium. This accordingly forms a rugged and compact unit of a portable nature, free from the danger of electrical shocks and capable of supplying the X-ray or discharge tube with relatively high potential energy.

Heretofore, one of the most objectionable features in apparatus of this type is that upon fallure of the tube, requiring replacement thereof,

it has been necessary to disconnect the conductors from the tube terminals while they are immersed in the oil. This at best is an unpleasant and time-consuming task and usually requires the services of a skilled mechanic or a re-shipment of the apparatus back to the manufacturer, particularly in instances where puncture of the glass envelope occurs, causing particles to fall upon the transformer, thus necessitating draining off of the cooling and insulating medium to remove such particles. Prior to re-filling of the container with a cooling and insulating medium, it is frequently necessary to subject the coils of the transformer to a new vacuum treatment.

In accordance with the present invention, all of the essential features requisite in shockproof high voltage apparatus are retained by immersing the high tension source and all high tension terminals in oil so as to enable the utilization of a foreshortened tube, as in prior art devices, to eliminate the danger of shocks to operator or patient.

In addition, the former objectionable feature of requiring the mechanic or operator to reach into the oil to disconnect the tube terminals and 1939, Serial No. 259,087

remove the same is eliminated by supporting the high voltage tube in such a manner that it may be removed from the casing. Moreover, upon removal of the tube, the volume of oil normally displaced by the tube when immersed therein is automatically increased so that none of the coils of the current supplying transformers are exposed, which would otherwise require a new vacuum treatment.

For a better understanding of the novel features of the present invention reference may be had to the accompanying drawing wherein:

Fig. 1 is a cross-sectional View of a shockproof unit constructed in accordance with the present invention and showing such apparatus during normal operation, and

Fig. 2 is a partial sectional view showing the apparatus in position for removal of the X-ray tube.

Referring now to the drawing in detail, the structure shown comprises a casing 5 provided with an annular portion 6 surrounding an X-ray pervious window I provided in the wall of the casing 5, which annular portion 6 is threadedly engaged by a suitable directional cone 8, as is well known in the art.

A high voltage transformer 9 is supported within the casing 5, the primary of which may be connected to the usual source of commercial supply by means of a cable H]. A cover plate I2 forms a closure for the top of the casing, which cover plate is provided with a suitable hinge 13 to enable a partial raising of the cover plate, as hereinafter more fully described.

A filament or low voltage transformer Hi is rigidly secured to the cover plate [2 and depends therefrom with its primary connected to the commercial source of supply in the same manner as the high voltage transformer 9. An X-ray tube I5 is shown supported by a pair of depending separable brackets it rigidly secured to the cover plate l2 with the thermionic cathode (not shown) of the X-ray tube being connected to the secondary winding of the low voltage transformer 14 by conductors such as ii and contact terminals as hereinafter described. The anode and cathode electrodes of the X-ray tube l5 are connected to the secondary winding of the high voltage transformer 9 by spring contact terminals l8.

As shown in Fig. 1, the casing 5 is filled with a cooling and insulating medium having high dielectric strength, such as oil 19, and the cover plate 12 is secured in a closed position with suitable means, such as a gasket 29, being employed to prevent leakage. When, for any reason, it is desired to replace the X-ray tube, the cover plate is first loosened and lifted, as shown in 2, by movement of the hinge 13 about its pivotal connection 22 to the casing. Inasmuch as the filament transformer I4 is secured to the cover plate I 2, removal of the X-ray tube it? from the body of cooling and insulating medium is, which it formerly displaced, tends to cause such a decrease in volume of the medium id as would normally expose the windings of the filament transformer l4, and more especially the secondary coils of the high voltage transformer 9. If this should occur, it would require a new vacuum treatment due to exposure of the windings to air before the transformer 9 could safely be again immersed in the cooling and insulating medium.

Accordingly, the present invention contemplates the automatic displacement of the volume of cooling and insulating medium upon removal of the Y-ray tube therefrom. By this it is meant that while the volume in terms of quantity remains constant, the body or volume as a whole is shifted, so that the level of the medium remains constant, particularly when the discharge device is removed therefrom. Consequently, wherever change in volume or replacement of the volume is recited in this specification or in the claims, it is to be understood that such does not refer to an increase or decrease in volume in terms of quantity, but such is to be given the definition above stated.

To this end the casing ii is provided with an offset portion having an expansible and contractable bellows 2-5 disposed therein with the diaphragm 25 of the bellows connected to a plunger 26. The hinge l3 pivotally connected to a small link 2i, the latter of which in turn is connected to an elongated link 28 having its opposite extremity pivotally connected to a lug 29 projecting outwardly from the offset portion 23 of the casing.

This elongated link 26 is provided with an arcuate portion 39 adapted to contact the plunger .26. With the cover plate it in its closed oil-tight position, as shown in Fig. l, the bellows 24 is in its contracted position with the volume of cooling and insulating medium i 9 being sufficient to completely fill the casing 5, as shown. When it is necessary for any reason to remove the X-ray tube from the casing for replacement or repair, the cover plate 52 is raised in the manner above described and as shown in Fig. 2.

Instead of a decrease in the level of the oil resulting upon raising of the X-ray tube due to the volume of oil formerly displaced thereby, the rotation of the hinge it about the pivotal point 22 causes movement of the link members 27 and 28 toward the casing 5, or to the left as shown in the figures, with the result that the elongated link member 213 depresses the plunger 26, causing an expansion of the bellows diaphragm 25 which thus automatically raises the level of oil to, in effect, replace the same by the amount equal to that formerly displaced by the Xray tube 85 when immersed therein.

Also, this displacement in the volume of the cooling and insulating medium it automatically occurs simultaneously with raising of the cover plate i2 so that the coils of the low voltage transformer M are permanently below the oil level, even though raised with the cover plate and X-ray tube. Thus at no time are the windings of the low voltage transformer exposed, so that no new vacuum treatment is necessary whenever an X-ray tube needs replacing.

A further advantage is the construction herein described, wherein the low voltage filament trans" former for the X-ray tube is mounted on the-same cover plate with the tube, resides in the fact that the filament conductors H can be rigidly attached to the tube by suitable terminals (not shown) and spring contacts [8 can be employed for the two high tension terminals which connect the secondary coils of the high'voltage transformer 9 to the electrodes of the X-ray tube. This is of advantage because of the well known fact that the condition of the filament connection is extremely critical since small fluctuations of contact resistance will appreciably affect the magnitude of the Xray tube current which is eliminated by rigidly connected terminals for the conductors, whereas conditions regarding the high voltage connections are far less critical, enabling the utilization of the spring contact terminals it as previously mentioned.

After replacement of the X-ray tube by removal of the old tube and the positioning of the new tube in the depending separable brackets I6, the cover is again lowered and secured in place, as shown in Fig. 1. This causes an inverse movement of the link members 2'! and 28, allowing the plunger 26 to move outwardly, thus enabling the cooling and insulating medium l9 within the easing 5 to expand and compress the bellows 24 an amount equal to that of the cooling and. insulating medium displaced by the immersed X-ray tube i5 together with the depending brackets l6, after which the cover plate i2 is secured in place in an oil-tight manner to enable movement of the entire casing in all directions during operation without leakage thereof.

It will thus become obvious to those skilled in the art that a shockproof apparatus is herein provided wherein all high tension carrying parts are immersed in a cooling and insulating medium, such as oil, which, having a higher dielectric strength than air, enables the utilization of a foreshortened X-ray, or discharge tube with a shorter spacing between all high tension carrying parts than would normally be required for the same applied voltage if operating in air.

Moreover, the discharge tube may be readily removed for replacement or repair by raising the l hinged cover plate so that the tube is entirely free or" the cooling and insulating medium, facilitating its removal or repair, and at the same time the volume of the cooling and insulating medium within the container is automatically displaced by movement of the cover plate so that none of the windings of the transformer are exposed, which might otherwise necessitate a new vacuum treatment.

Although one specific embodiment of the present invention has been shown and described, it is to be understood that other modifications thereof may be made Without departing from the spirit and scope of the appended claims.

I claim:

1. In an electron discharge apparatus, the combination of a casing provided with a source of high potential electrical energy therein, an electron discharge tube having an anode and a filamentary cathode connected to said high potential source for energization thereby and normally disposed in said casing, a cooling and insulating medium immersing said high potential source andsaid discharge tube, means for removing said discharge tube from said cooling and insulating medium for replacement or repair, and means operable upon removal of said tube from said cooling and insulating medium to cause a change in volume thereof to compensate for the medium normally displaced by said dis" charge tube when immersed therein.

2. In an electron discharge apparatus, the combination of a casing provided with a source of high potential electrical energy therein, an electron discharge tube having an anode and a filamentary cathode connected to said high potential source for energization thereby and normally disposed in said casing, a cooling and insulating medium immersing said high potential source and said discharge tube, means operable to remove said discharge tube from said cooling and insulating medium for replacement or repair, and means automatically responsive to operation of said last mentioned means to cause a change in volume of said cooling and insulating medium to compensate for the medium normally displaced by said discharge device when immersed. therein.

3. In an electron discharge apparatus the combination of a casing provided with a source of high potential electrical energy therein and having a removable cover plate, an electron discharge tube having an anode and a filamentary cathode supported by said cover plate within said casing and connected to said high potential source for energization thereby, a cooling and insulating medium immersing said discharge tube and substantially filling said casing, means whereby said cover plate may be raised to remove said discharge tube from said cooling and insulating medium for replacement or repair, and means operable upon raising of said cover plate to cause a change in the volume of said cooling and insulating medium to compensate for the medium normally displaced by said discharge tube when immersed therein to maintain said casing filled with said medium after said discharge tube is removed therefrom.

4. In an electron discharge apparatus, the

combination of a casing provided with a source of high potential electrical energy therein and having a removable cover plate, an electron discharge tube having an anode and a filamentary cathode supported by said cover plate within said casing and connected to said high potential source for energization thereby, a cooling and insulating medium immersing said discharge tube and substantially filling said casing, means whereby said cover plate may be raised to remove said discharge tube from said cooling and insulating medium for replacement or repair, and an expansible and contractable bellows disposed in said casing and operable upon raising of said cover plate to cause an expansion of said bellows with an attendant change in the volume of said cooling and insulating medium to compensate for the medium normally displaced by said discharge tube when immersed therein for the purpose of maintaining said casing filled with said medium after said discharge tube is removed therefrom,

5. In an electron discharge apparatus, the combination of a casing provided with a source of high potential electrical energy therein and having a removable cover plate, an electron discharge tube having an anode and a filamentary cathode supported by said cover plate within said casing and connected to said high potential source for energization thereby, a cooling and insulating medium immersing said discharge tube and substantially filling said casing, a hinge pivotally connected to said casing whereby said cover plate may be raised to remove said discharge tube from said cooling and insulating medium for replacement or repair, and an expansible and contractable bellows disposed in said casing and operably connected to said hinge to cause an expansion of said bellows with an attendant change in the volume of said cooling and insulating medium to compensate for the medium normally displaced by said discharge tube when immersed therein for the purpose of maintaining said casing filled with said medium after said discharge tube is removed therefrom.

6. In a shoclrproof X-ray apparatus, the combination of a casing provided with a high potential transformer therein and having a removable cover plate, an X-ray tube having an anode and a filamentary cathode supported by said cover plate within said casing and connected to said high tension transformer for energization thereby, a low voltage transformer supported by said cover plate and connected to the cathode of said X-ray tube for supplying heating energy thereto, a cooling and insulating medium immersing said X-ray tube and both of said transformers and substantially filling said casing, means whereby said cover plate may be raised to remove said X-ray tube from said cooling and insulating medium for replacement or repair, and means operable upon raising of said cover plate to cause a change in the volume of said cooling and insulating medium to compensate for the medium normally displaced by said X-ray tube when immersed therein for the purpose of maintaining said casing filled with said medium after said X-ray tube is removed therefrom to prevent exposure of the windings of said high voltage transformer to the atmosphere to eliminate the necessity for subjecting the windings of said low voltage transformer to a vacuum treatment.

7. In a shockproof X-ray apparatus, the combination of a casing provided with a high potential transformer therein and having a removable cover plate, an X-ray tube having an anode and a filamentary cathode supported by said cover plate within said casing and connected to said high tension transformer for energization thereby, a low voltage transformer supported by said cover plate and connected to the cathode of said X-ray tube for supplying heating energy thereto, a cooling and insulating medium immersing said X-ray tube and both of said transformers and substantially filling said casing, a hinge pivotally connected to said casing whereby said X-ray tube and low voltage transformer may be raised to remove said X-ray tube from said cooling and insulating medium for replacement or repair, and an expansible and contractable bellows disposed within said casing and operably connected to said hinge to cause an expansion of said bellows and an attendant change in the volume of said cooling and insulating medium to compensate for the medium normally displaced by said X-ray tube when immersed therein for the purpose of maintaining said casing filled with said medium after said X-ray tube is removed therefrom to prevent exposure of said high voltage transformer to the atmosphere, thus eliminating the necessity for subjecting the windings thereof to a vacuum treatment. 

